President Trump told Russian officials last week that he had fired the "nut job" FBI Director James Comey to ease the pressure of the mounting investigation into his campaign's ties to Russia, according to a report from The New York Times.

"I just fired the head of the F.B.I. He was crazy, a real nut job," Trump told the Russian foreign minister and U.S. ambassador on May 10 during an Oval Office meeting, according to a transcript of the meeting read to The Times by a U.S. official. "I faced great pressure because of Russia. That's taken off."

White House press secretary Sean Spicer did not dispute the account of the conversation to The Times and, in a statement to NPR, argued that the Russia investigation was harming U.S. foreign policy.

"The President has always emphasized the importance of making deals with Russia as it relates to Syria, Ukraine, defeating ISIS and other key issues for the benefit and safety of the American people. By grandstanding and politicizing the investigation into Russia's actions, James Comey created unnecessary pressure on our ability to engage and negotiate with Russia," Spicer said. "The investigation would have always continued, and obviously, the termination of Comey would not have ended it. Once again, the real story is that our national security has been undermined by the leaking of private and highly classified conversations."

The May 10 meeting with Russian Foreign Minister Sergey Lavrov and Ambassador Sergey Kislyak came one day after Trump abruptly fired Comey, which the White House argued at first was because of a memo from Deputy Attorney General Rod Rosenstein pointing to Comey's mismanagement of the investigation into Democratic nominee Hillary Clinton's private email server. Trump later said he had already decided to fire Comey regardless of Rosenstein's memo, which the deputy attorney general confirmed to Congress this week.

At the same meeting, The Washington Postreported earlier this week, Trump had given the Russians "highly classified information" that "jeopardized a critical source of intelligence" on ISIS that came from a key ally, which, according to later reports, was Israel. No American reporters were allowed in to document the meeting, only a Russian Foreign Ministry photographer.

The Times report on Friday afternoon is just the latest bombshell story over the past week and adds to mounting headaches for the White House just as Trump has departed for his first foreign trip as president.

Amid growing pressure, Rosenstein, the deputy attorney general, appointed former FBI Director Robert Mueller as a special counsel to oversee the Department of Justice's Russia investigation. Mueller was tapped for that post the day after another report from The Times, subsequently confirmed to NPR by two sources, that Trump had asked Comey to scuttle the investigation into former national security adviser Michael Flynn. Flynn was let go after less than a month on the job after it was revealed he had misled Vice President Pence over his conversation during the transition with Kislyak about U.S. sanctions.

"There is no collusion between, certainly myself and my campaign, but I can only speak for myself and the Russians. Zero," Trump said Thursday during a news conference with Colombian President Juan Manuel Santos.